Successive Eruptions Research Articles

Age, distance, and geochemical evolution within a monogenetic volcanic field: Analyzing patterns in the Auckland Volcanic Field eruption sequence

The Auckland Volcanic Field (AVF) is a young active monogenetic basaltic field, which contains ∼50 volcanoes scattered across the Auckland metropolitan area. Understanding the temporal, spatial, and chemical evolution of the AVF during the last c.a. 250 ka is crucial in order to forecast a future eruption. Recent studies have provided new age constraints and potential temporal sequences of the past eruptions within the AVF. We use this information to study how the spatial distribution of the volcanic centers evolves with time, and how the chemical composition of the erupted magmas evolves with time and space. We seek to develop a methodology which compares successive eruptions to describe the link between geochemical and spatiotemporal evolution of volcanic centers within a monogenetic volcanic field. This methodology is tested with the present day data of the AVF. The Poisson nearest neighbor analysis shows that the spatial behavior of the field has been constant overtime, with the spatial distribution of the volcanic centers fitting the Poisson model within the significance levels. The results of the meta‐analysis show the existence of correlations between the chemical composition of the erupted magmas and distance, volume, and time. The apparent randomness of the spatiotemporal evolution of the volcanic centers observed at the surface is probably influenced by the activity of the source. The methodology developed in this study can be used to identify possible relationships between composition trends and volume, time and/or distance to the behavior of the source, for successive eruptions of the AVF.

The interaction and eruption of two adjacent filaments

We present a case study of two successive filament eruptions at the southeast limb of the Sun observed by Solar Dynamics Observatory (SDO) on 2012 April 19. At the initial stage of the first filament (F1) eruption, one leg of the F1 moved toward the second filament (F2) and swept the F2. The interaction between two filaments occurred. After the leg of the F1 swept the F2, it returned from northeast to southwest following the F1 expansion. During the F1 eruption, the middle of the F1 exhibited an obvious twisted structure. The rising speed of the F1 was 85.6 km/s. The partial material of the F1 fell back to the surface along the other leg of the F1 after the F1 eruption and the falling speed was 311.6 km/s. A CME was observed by SOHO/LASCO after the F1 eruption. One of the bright flare ribbons and the dimming regions formed after the F1 eruption were found to move toward the F2. The propagation speeds of the flare ribbons were 4.7 km/s and 4.1 km/s and the propagation speeds of the dimmings were 3 km/s and 6.3 km/s. The small active region was emerging in the northern flank of the F2. The ejection and the falling plasma in the small active region produced the disturbance to the right part of the F2. When the F1 erupted, the large-scale overlying coronal loops of the F1 were pushed out toward the southeast of the Sun by its expanding. During the F1 eruption, the large-scale overlying coronal loops of the F2 began to open toward the southeast. Following the opening of the large-scale overlying coronal loops, the F2 became instable and began to erupt. The rising speed of the F2 was 300.1 km/s. A two-ribbon flare and a weak CME were formed after the F2 eruption. These observations evidenced that the interaction of two filaments and the opening of the large-scale overlying coronal loops caused by the F1 eruption are the most important reason that led to the F2 eruption. Our observations also support the standard solar flare model.

Successive filament eruptions within one solar breakout event

AbstractThe magnetic breakout model has been widely used to explain solar eruptive activities. Here, we apply it to explain successive filament eruptions occurred in a quadrupolar magnetic source region. Based on the high temporal and spatial resolution, multi-wavelengths observations taken by the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamic Observatory (SDO), we find some signatures that support the occurrence of breakout-like external reconnection just before the start of the successive filament eruptions. Furthermore, the extrapolated three-dimensional coronal field also reveals that the magnetic topology above the quadrupolar source region resembles that of the breakout model. We propose a possible mechanism within the framework of the breakout model to interpret the successive filament eruptions, in which the so-called magnetic implosion mechanism is firstly introduced to be the physical linkage of successive filament eruptions. We conclude that the structural properties of coronal fields are important for producing successive filament eruptions.

Seismological evidence for long-term and rapidly accelerating magma pressurization preceding the 2009 eruption of Redoubt Volcano, Alaska

Successful eruption forecasts are heavily dependent on the recognition of well-established patterns in volcano monitoring data. Therefore, it is critical to develop, in retrospect, an understanding of the physical basis for cases of abnormal precursory behavior, as the basis for (a) a complete understanding of the range of precursory signals that may be expected at a particular volcano and (b) development of new monitoring approaches to detect more subtle signals of the underlying processes responsible for common patterns of seismic unrest. Here, using a hybrid analysis of shear-wave splitting (SWS) and double-couple fault-plane solutions (FPS), we document the timing and nature of local stress field changes in the months to days preceding the 2009 eruption of Redoubt Volcano, Alaska, which was characterized by an abnormally long period of precursory low-frequency seismicity reflected in multiple escalations of alert levels prior to the eruption. We find that an approximately ~90° change in the polarization of fast S-wavelets (Φ) accompanied the earliest signs of seismic unrest in 2008 and continued through the eruption before diminishing in 2009. A similar change in the orientation of VT FPS occurred 18–48h prior to the eruption onset on March 23, 2009, but almost two months after a strong increase in the rate of shallow VT earthquakes. Combined, our SWS and FPS results show the earliest-, and latest-known changes in seismic monitoring data, respectively, and are suggestive of a protracted period of slow magma ascent followed by a short period of rapidly increasing magma pressurization beneath the volcano. These results demonstrate the power of a combined stress-field analysis for clarifying the processes driving ambiguous seismic unrest at active volcanoes.

Characteristics of CO2‐driven cold‐water geyser, Crystal Geyser in Utah: experimental observation and mechanism analyses

AbstractGeologic carbon capture and storage (CCS) is an option for reducing CO2 emissions, but leakage to the surface is a risk factor. Natural CO2 reservoirs that erupt from abandoned oil and gas holes leak to the surface as spectacular cold geysers in the Colorado Plateau, United States. A better understanding of the mechanisms of CO2‐driven cold‐water geysers will provide valuable insight about the potential modes of leakage from engineered CCS sites. A notable example of a CO2‐driven cold‐water geyser is Crystal Geyser in central Utah. We investigated the fluid mechanics of this regularly erupting geyser by instrumenting its conduit with sensors and measuring pressure and temperature every 20 sec over a period of 17 days. Analyses of these measurements suggest that the timescale of a single‐eruption cycle is composed of four successive eruption types with two recharge periods ranging from 30 to 40 h. Current eruption patterns exhibit a bimodal distribution, but these patterns evolved during past 80 years. The field observation suggests that the geyser's eruptions are regular and predictable and reflect pressure and temperature changes resulting from Joule–Thomson cooling and endothermic CO2 exsolution. The eruption interval between multiple small‐scale eruptions is a direct indicator of the subsequent large‐scale eruption.

Radiative forcing and climate impact resulting from SO2 injections based on a 200,000-year record of Plinian eruptions along the Central American Volcanic Arc

We present for the first time a self-consistent methodology connecting volcanological field data to global climate model estimates for a regional time series of explosive volcanic events. Using the petrologic method, we estimated SO2 emissions from 36 detected Plinian volcanic eruptions occurring at the Central American Volcanic Arc (CAVA) during the past 200,000 years. Together with simple parametrized relationships collected from past studies, we derive estimates of global maximum volcanic aerosol optical depth (AOD) and radiative forcing (RF) describing the effect of each eruption on radiation reaching the Earth’s surface. In parallel, AOD and RF time series for selected CAVA eruptions are simulated with the global aerosol model MAECHAM5-HAM, which shows a relationship between stratospheric SO2 injection and maximum global mean AOD that is linear for smaller volcanic eruptions (<5 Mt SO2) and nonlinear for larger ones (≥5 Mt SO2) and is qualitatively and quantitatively consistent with the relationship used in the simple parametrized approximation. Potential climate impacts of the selected CAVA eruptions are estimated using an earth system model of intermediate complexity by RF time series derived by (1) directly from the global aerosol model and (2) from the simple parametrized approximation assuming a 12-month exponential decay of global AOD. We find that while the maximum AOD and RF values are consistent between the two methods, their temporal evolutions are significantly different. As a result, simulated global maximum temperature anomalies and the duration of the temperature response depend on which RF time series is used, varying between 2 and 3 K and 60 and 90 years for the largest eruption of the CAVA dataset. Comparing the recurrence time of eruptions, based on the CAVA dataset, with the duration of climate impacts, based on the model results, we conclude that cumulative impacts due to successive eruptions are unlikely. The methodology and results presented here can be used to calculate approximate volcanic forcings and potential climate impacts from sulfur emissions, sulfate aerosol or AOD data for any eruption that injects sulfur into the tropical stratosphere.

Need for further clarity on optimal approach to ectopic canines

Randomised controlled trial. Patients between 8-13 years of age with either unilateral or bilateral PDC diagnosed on radiograph with the presence of mild crowding at the maxillary arch and/or molar relation showing Class II tendency were included. The head gear group (HG) used cervical pull headgear alone for one year for 12-14 hours a day, while the rapid maxillary expansion/headgear (RME/HG) group were treated with a banded rapid maxillary expander, (7 mm of active expansion; at the end of expansion all patients retained the expander for six months), followed by use of a cervical pull headgear as in the HG group. A control group received no active treatment. A successful outcome for PDC was defined as the full eruption of the tooth, thus permitting bracket positioning for final arch alignment at 18 months after the initial observation. Sixty of the 64 patients who entered the trial were available for final assessment. Successful eruption was 85.7% in the RME/HG group, 82.3% in the HG group and 36% in the control group. There was no statistically significant difference between the HG and RME/HG groups. The use of rapid maxillary expansion and headgear (or headgear alone) in PDC cases increases the success rate of eruption of the canine significantly (almost three times more than in untreated controls).

Residents’ journal review

Residents’ journal review

Unusual intraosseous transmigration of impacted tooth

Transmigration of an impacted tooth through the symphyseal suture is a rare and special developmental anomaly of unknown etiology that is unique to the mandibular canine. Maxillary canine transmigration is even rarer. Transmigrated canines are particularly significant due to the aesthetic and functional importance. A maxillary lateral incisor crossing the mid-palatal suture has never been reported in the literature. The aim of this report is to present the first case of simultaneous transmigration of a lateral incisor and canine in the maxilla. The paper also reports four unusual cases of unilateral canine transmigration in the maxilla and mandible and successful eruption of one of the transmigrated mandibular canines following orthodontic traction. Etiology of transmigration and its clinical considerations are also discussed.

Volcanic hazard assessment for the Canary Islands (Spain) using extreme value theory

Abstract. The Canary Islands are an active volcanic region densely populated and visited by several millions of tourists every year. Nearly twenty eruptions have been reported through written chronicles in the last 600 yr, suggesting that the probability of a new eruption in the near future is far from zero. This shows the importance of assessing and monitoring the volcanic hazard of the region in order to reduce and manage its potential volcanic risk, and ultimately contribute to the design of appropriate preparedness plans. Hence, the probabilistic analysis of the volcanic eruption time series for the Canary Islands is an essential step for the assessment of volcanic hazard and risk in the area. Such a series describes complex processes involving different types of eruptions over different time scales. Here we propose a statistical method for calculating the probabilities of future eruptions which is most appropriate given the nature of the documented historical eruptive data. We first characterize the eruptions by their magnitudes, and then carry out a preliminary analysis of the data to establish the requirements for the statistical method. Past studies in eruptive time series used conventional statistics and treated the series as an homogeneous process. In this paper, we will use a method that accounts for the time-dependence of the series and includes rare or extreme events, in the form of few data of large eruptions, since these data require special methods of analysis. Hence, we will use a statistical method from extreme value theory. In particular, we will apply a non-homogeneous Poisson process to the historical eruptive data of the Canary Islands to estimate the probability of having at least one volcanic event of a magnitude greater than one in the upcoming years. This is done in three steps: First, we analyze the historical eruptive series to assess independence and homogeneity of the process. Second, we perform a Weibull analysis of the distribution of repose time between successive eruptions. Third, we analyze the non-homogeneous Poisson process with a generalized Pareto distribution as the intensity function.

Nearly contemporaneous evolution of the A- and S-type fractionated granites in the Krušné hory/Erzgebirge Mts., Central Europe

The Krušné hory/Erzgebirge Mountains is one of the best-known provinces of granite magmatism and associated metallogenesis in Europe. Variscan magmatic activity in the Krušné hory/Erzgebirge area spanned the period from 330 to 295Ma. For much of this time, two types of magma were generated and emplaced in close proximity in this province. Strongly peraluminous P-rich (S-type) melts were formed alongside slightly peraluminous P-poor melts (A-type). Two suites of strongly peraluminous P, F, Li, Rb, Cs, U, Sn-rich and Zr, Th, Y, HREE-poor magmas were intruded in rapid succession over a period of about 10Ma (about 330–320Ma) over the entire region of the Krušné hory. Several peraluminous rhyolitic dykes near Gottesberg mark an isolated event at about 295Ma. Slightly peraluminous F, Li, Rb, Cs, Sn, Zr, Y, HREE-rich and P-poor magmas were intruded in several events separated in space and time (325–295Ma). Both magmatic episodes culminated with strongly fractionated subvolcanic granite intrusions, accompanied by explosive brecciation and followed by Sn+W mineralization of greisen type. Successive volcanic eruption of rhyolites and dacites of S-type, and rhyolites of A-type form the fill of the Altenberg-Teplice Caldera (ATC), thus demonstrating the close temporal and spatial relationship between these two types of magma. When these two geochemically distinct types of rock are in direct contact, then the rocks of A-type are always younger. The absolute time difference between the two types can range from less than 1Ma (the first eruption of the Teplice rhyolite versus the Schönfeld dacite in the ATC) to about 15Ma (eruption of rhyolites at Gottesberg versus emplacement of the Eibenstock granite). The assumed protolith of all late-Variscan granites in the area of Krušné hory/Erzgebirge is a mixture of fertile quartzo-feldspathic rocks with micaceous metapelites enriched in LILE and Sn+W. The differences in chemical composition of S- and A-type melts originated from local changes in the proportion of quartzo-feldspathic and pelitic lithologies, different pT-conditions of melting, the degree of melting, and the degree of metamorphic dehydratation of the protolith prior to the melting.

Modifying therapeutic objectives in accordance with patient’s ethnicity

We took orthodontic records and began full-banded and bonded treatment soon after F, a 13 year 3 month old girl, who consulted us in 2007 at our office in a city of southwest France. F.’s loss of all four first premolars as an accompaniment to mechano-therapy was compensated for by the eventual successful eruption of her third molars. We were able to remove her appliances in 2009 as we had promised, before her 16th birthday.

A time series of filament eruptions observed by three eyes from space: from failed to successful eruptions

We present stereoscopic observations of six sequential eruptions of a filament in the active region NOAA 11045 on 2010 Feb 8, with the advantage of the STEREO twin viewpoints in combination with Earth's viewpoint from SOHO instruments and ground-based telescopes. The last one of the six eruptions is a coronal mass ejection, but the others are not. The flare in this successful one is more intense than in the others. Moreover, the velocity of filament material in the successful one is also the largest among them. Interestingly, all the filament velocities are found to be proportional to the power of their flares. We calculate magnetic field intensity at low altitude, the decay indexes of the external field above the filament, and the asymmetry properties of the overlying fields before and after the failed eruptions and find little difference between them, indicating the same coronal confinement exists for both the failed and successful eruptions. The results suggest that, besides the confinement of the coronal magnetic field, the energy released in the low corona should be another crucial element affecting a failed or successful filament eruption. That is, a coronal mass ejection can only be launched if the energy released exceeds some critical value, given the same initial coronal conditions.

Fluid-dynamic modeling of mud volcanism

The eruptive behavior of mud volcanoes has been explored in several forward and inversion models. The forward models, based on classical continuum-mechanics, simulate the non-stationary processes of gas seepage and two-phase gas-mud flow through the conduit of a mud volcano, as well as the quasi-stationary gas frontal drive that pushes mud out, and the subsequent gas escape into the air. Forward modeling is performed with reference to the pressure and temperature dependence of the gas viscosity and compressibility. The inversion for the depth to the mud column base has yielded an unambiguous solution. According to the modeling results, the depths to the mud base and to the gas reservoir are controlled mainly by conduit permeability, while the interval between two successive eruption events depends on the gas/mud viscosity ratio. The modeling has allowed estimates for the mud breccia portion remaining in the conduit by the time of eruption, and for the subsurface volcano thickness inferred using a hydraulic-fracture model of the related gryphon field, and for the rate of gas release at the beginning of an eruption.

Effect of RME and headgear treatment on the eruption of palatally displaced canines: A randomized clinical study

To determine the effectiveness of orthodontic treatment finalized on the maintenance/improvement the upper arch perimeter to assist in the successful eruption of palatally displaced maxillary canines (PDCs). The randomized prospective design comprised 64 subjects with PDCs who were randomly assigned to one of three groups: cervical pull headgear (HG); rapid maxillary expansion and cervical pull headgear (RME/HG); or untreated control group (CG). Panoramic radiographs and lateral cephalograms were evaluated at the time of initial observation (T1) and after an average period of 18 months (T2). At T2 the success of canine eruption was evaluated. A superimposition study on lateral cephalograms was undertaken to evaluate the T1-T2 changes in the sagittal position of the upper molars in the three groups. The prevalence of successful eruption was 85.7% in the RME/HG group and 82.3% in the HG group. Both these prevalence rates were significantly greater than the success rate in untreated control subjects (36%). The cephalometric superimposition study showed a significant mesial movement of the upper first molars in the CG compared with the HG and RME/HG groups. The use of rapid maxillary expansion and headgear (or headgear alone) in PDC cases increases the success rate of eruption of the canine significantly (almost three times more than in untreated controls).

MANAGEMENT OF THE IMPACTED TOOTH ASSOCIATED WITH DENTIGEROUS CYST IN AUTISTIC YOUNG PATIENTS

Autism is a developmental, neuropsychiatric disorder that begins in early childhood. A patient with autism seen in the dental office frequently may have many complications. Therefore, it may be needed to consider modified or alternative therapy for dental care of autistic patients. This is the case of a 16-year old boy who have autism. He came to the department of the pediatric dentistry, Yonsei University Dental Hospital, for evaluation and treatment of dentigerous cyst associated with impacted teeth(#33,34,35). Under daily hospitalization and general anesthesia, the cyst was enucleated with surgical extraction of #34 and autotransplantation of #33,35. And during the periodic dental followup, apexification of #33,35 was performed for periapical lesion and root maturity. At 2 year 6 months follow- up, now, bony healing was completed and there are some complications like external resorption of #33 and space loss of #34 area. Generally, the marsupialization has been widely recommended for treatment of dentigerous cyst. However, in this case, there is a little possibility of spontaneous eruption after marsupialization considering of patient's age, location and angulation of the impacted tooth, root maturity. And there is necessity to choose the treatment that has low recurrence risk and needs short-term follow-up for autism. Above all, poor oral hygiene and lack of cooperation for decompression treatment is a matter of primary consideration. Consequently, enucleation of the cyst was chosen for the final treatment plan in this case. It is important to consider the conditions that affect the eruption of a dentigerous cyst-associated tooth to predict the successful eruption and special health care needs of the patient when the treatment plan is settled.

Geostatistical prediction of future volcanic eruption and risk assessment for the Mount Cameroon Volcano.

This study presents a statistical analysis forecasting a possible future volcanic eruption in Mount Cameroon. The study is primarily undertaken to assess the risk, determine the frequency of the successive eruptions and from this, forecast a possible future eruption of the Mount Cameroon volcano. This will assist in future planning and possibly put in place hazard mitigation strategies that will forestall the loss of lives and property. Results show that the series of Mount Cameroon eruptions are random and independent of time. Also, it is predicted within the limits of any reasonable doubt that the interval for the next major eruption that will emit lava with a volume of about 10million m3 is probably in the year 2022. This extrapolation is in line with the May 28, 2000 eruption barely fourteen months after the March – April 1999 eruption. However, the timing may be earlier or later and the volume may be more or less since the predicted values are approximations.

Explosive volcanic eruptions triggered by cosmic rays: Volcano as a bubble chamber

Volcanoes with silica-rich and highly viscous magma tend to produce violent explosive eruptions that result in disasters in local communities and that strongly affect the global environment. We examined the timing of 11 eruptive events that produced silica-rich magma from four volcanoes in Japan (Mt. Fuji, Mt. Usu, Myojin-sho, and Satsuma-Iwo-jima) over the past 306 years (from AD 1700 to AD 2005). Nine of the 11 events occurred during inactive phases of solar magnetic activity (solar minimum), which is well indexed by the group sunspot number. This strong association between eruption timing and the solar minimum is statistically significant to a confidence level of 96.7%. This relationship is not observed for eruptions from volcanoes with relatively silica-poor magma, such as Izu-Ohshima. It is well known that the cosmic-ray flux is negatively correlated with solar magnetic activity, as the strong magnetic field in the solar wind repels charged particles such as galactic cosmic rays that originate from outside of the solar system. The strong negative correlation observed between the timing of silica-rich eruptions and solar activity can be explained by variations in cosmic-ray flux arising from solar modulation. Because silica-rich magma has relatively high surface tension (~ 0.1 Nm −1), the homogeneous nucleation rate is so low that such magma exists in a highly supersaturated state without considerable exsolution, even when located relatively close to the surface, within the penetration range of cosmic-ray muons (1–10 GeV). These muons can contribute to nucleation in supersaturated magma, as documented by many authors studying a bubble chamber, via ionization loss. This radiation-induced nucleation can lead to the pre-eruptive exsolution of H 2O in the silica-rich magma. We note the possibility that the 1991 Mt. Pinatubo eruption was triggered by the same mechanism: an increase in cosmic-ray flux triggered by Typhoon Yunya, as a decrease in atmospheric pressure results in an increase in cosmic-ray flux. We also speculate that the snowball Earth event was triggered by successive large-scale volcanic eruptions triggered by increased cosmic-ray flux due to nearby supernova explosions.

An RCT on treatment of palatally displaced canines with RME and/or a transpalatal arch

To investigate the effect of rapid maxillary expansion (RME) and/or transpalatal arch (TPA) therapy in combination with deciduous canine extraction on the eruption of palatally displaced canines (PDCs). Hundred and twenty subjects were enrolled in an RCT based on PDCs diagnosed on panoramic radiographs and they were randomly assigned to one of four study groups. Three treatment groups (TGs) (RME followed by TPA therapy plus extraction of deciduous canines, RME/TPA/EC group, 40 subjects; TPA therapy plus extraction of deciduous canines, TPA/EC group, 25 subjects; extraction of deciduous canines, EC group, 25 subjects) were analyzed. A control group (CG, 30 subjects) received no orthodontic treatment. Prevalence rates of eruption of PDCs in the three TGs were compared with the CG at T2. Predictive features at T1 for successful canine eruption were tested in the three TGs. The prevalence of canine eruption was 80 per cent for the RME/TPA/EC group, 79 per cent for the TPA/EC group, 62.5 per cent for the EC group, versus 28 per cent in the CG, with statistically significant differences between all the groups, with the exception of the comparison between RME/TPA/EC and TPA/EC. Predictive pretreatment variables for the success of treatment were less severe sectors of canine displacement, prepubertal stages of skeletal maturity, and an open root apex of PDCs. The use of a TPA in absence of RME can be equally effective than the RME/TPA combination in PDC cases not requiring maxillary expansion, thus reducing the burden of treatment for the patient.

Subplinian fall deposits of Inyo Craters, CA

The Inyo volcanic chain in east central California last erupted explosively around 1350 A.D., ejecting 0.13 km 3 of tephra during four successive eruptions from the South Deadman, Obsidian Flow, and Glass Creek vents. The first two eruptions, from South Deadman, produced bent, pulsating subplinian columns separated by a period of column collapse. The Obsidian Flow eruption began with a phreatomagmatic vent-clearing blast, then continued with a sustained weak plume. The last and largest eruption, from the Glass Creek vent, produced a sustained subplinian eruption marked by a mid-eruption period of phreatomagmatism. These eruptions dispersed more than 0.27 km 3 tephra over an area greater than 9000 km 2. Inversion of the deposits produced column heights ranging between 6 and 20 km, with wind speeds in excess of 30 m/s, the highest windspeed included in the nomograms. Inversion results suggest limitations of the nomograms for weak plumes due to their simplifying assumptions regarding the influence of the eruption column on ambient flow.